Abstract
The phenomenon of water hammer in stagnant hot fluid systems has been manifested by the fracture of a number of cast iron valves and other components in power station low pressure feed water systems and other similar systems.
A comprehensive investigation proved necessary into all aspects of this phenomenon. The investigation involved a survey of water hammer events, experimental work, data acquisition, pressure testing, calculation of forces and the determination of the strength of individual components.
From this work has sprung a clear understanding of the sequence of events occurring when pressure is reduced on hot feed water and flash steam is produced which subsequently escapes or condenses and fluid columns recombine at speed and produce pressure pulses.
Experimental and theoretical work has revealed the magnitude of such pressure pulses and also revealed that steel pressure parts will not fail when subjected to the forces arising from thermodynamically induced water hammer, because steel pipes limit transient hydraulic pressures by dilating and steel valves are sufficiently strong.
The dynamic response of complex pipework system to stimulation by water hammer events requires further investigation, but practical experience indicates that failure of steel system components is unlikely from dynamic movements, although damage may be suffered by pipe hangers, seismic restraints etc.
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